1. Field of the Invention
The present invention relates to a starter for cranking an internal combustion engine.
2. Description of Related Art
An example of a starter for cranking an internal combustion engine is shown in JP-A-2002-276515. Relevant portions of this starter are briefly shown in FIGS. 5 and 6 attached hereto. The starter has two axes parallel to each other: one is an axis of an electric motor 100 having a pinion gear connected to its front end; and the other is an axis of a magnetic switch 110 for supplying electric power to the electric motor in an ON-OFF fashion and for driving the pinion gear toward a ring gear of the engine.
A yoke 120 of the electric motor 100 is sandwiched between a front housing 130 and a rear end frame 140, and the front housing 130 and the rear end frame 140 are connected to each other with a pair of through-bolts 150. The rear end frame 140 has a cylindrical bearing holder 141 at its center, and a rear end of an armature shaft 170 is supported by a bearing 160 held in the bearing holder 141. In this structure of the starter, there is a possibility that the bearing holder 141 be deformed when a large force is applied to the rear end frame 140 from the rear side thereof. If the bearing holder 141 is deformed, the armature shaft 170 will be prevented from smooth rotation.